1. Field of the Invention
The invention relates to a job separator which may be configured to convey printed sheets by changing two conveyance positions back and forth, with respect to a sheet conveyance direction, onto an output tray of an image recording apparatus, and also relates to the image recording apparatus including the job separator.
2. Description of Related Art
Known image recording apparatuses such as printers, copiers, and facsimiles, include a device for ejecting printed sheets to a front or rear position with respect to a sheet conveyance direction, alternating between front and rear positions according to each document created on a computer or a word processor. In a known image recording apparatus, a plurality of pairs of drive rollers are positioned a predetermined distance away from one another, near a sheet ejection portion and in an upstream side with respect to a sheet conveyance direction. One pair of conveyance rollers, which is positioned nearest the sheet ejection portion, includes a drive roller positioned such that an upper surface of a sheet faces the drive roller, and an auxiliary roller positioned such that a lower surface of the sheet faces the auxiliary roller. The auxiliary roller is moved closer to or further away from the drive roller by a piston positioned on the side of the auxiliary roller, and the piston advances and retreats, thereby moving the auxiliary roller closer to or further away from the sheet to be fed.
In a known image recording apparatus, when the auxiliary roller faces the drive roller, the sheet is ejected onto an output tray, such that the leading end of the sheet is positioned downstream from a position between the rollers, with respect to the sheet conveyance direction. When the auxiliary roller moves away from the drive roller, such that the auxiliary roller stops at a position that is withdrawn from the upstream side in the sheet conveyance direction, the auxiliary roller does not contact or guide the lower surface of the sheet to be ejected. In this position, the sheet drops down when the sheet reaches an upstream side of the output tray, with respect to the sheet conveyance direction. In this manner, a known image recording apparatus can, for each document requested, change a position of a sheet to be ejected onto the output tray between an upstream-side position and a downstream-side position, alternately, with respect to the sheet conveyance direction.
Nevertheless, in a known image recording apparatus, the movable auxiliary roller moves back and forth in the sheet conveyance direction, on the side facing the lower surface of the sheet to be ejected. In addition, the piston configured to move the auxiliary roller is positioned also on the side facing the lower surface of the sheet to be ejected. In order to maintain the number of sheets accommodated by the output tray, space is provided in the output tray to allow the auxiliary roller to freely move. As a result, the height of the image recording apparatus increases, which increases the overall size of the image recording apparatus and may prevent the production of compact image recording apparatuses.